1. Field of the Invention
The present invention relates to a blade driving device and an optical apparatus.
2. Description of the Related Art
For example, an optical apparatus such as a digital camera or a still camera employs a blade driving device provided with a driving member that drives blades.
In Japanese Unexamined Patent Application, First Publication No. 2014-66760, a blade driving device which includes a substrate having an aperture, first and second blades that open and close the aperture, and first and second actuators for driving the first and second blades, in which the first and second actuators respectively include first and second stators, first and second rotors, and first and second coils, and the first and second rotors are arranged so as to interpose at least one of the first and second coils therebetween, is described.
However, in recent years, in order to cope with an increase in the size of the blades due to an increase in the size of the aperture of the substrate or an increase in the speed of the driven blades, an increase in the output of the first and second actuators is required. In order to increase the output of the actuator, there is a need to increase the ampere-turn which is the product of the winding number of the coil and the current value.
However, in the blade driving device described in the related art, when the winding number of the coil is simply increased in order to realize an increase in the output, the electric wire length of the coil is increased and the resistance is also increased, resulting in a reduction in the winding efficiency. In addition, thickening of the coil occurs, and thus the thickness of the blade driving device is increased. In particular, in a recent optical apparatus, a reduction in the thickness has been required. Therefore, there is an object to suppress an increase in the thickness while realizing an increase in the output of the blade driving device.